White doesn't mind playing slowly to prevent the b5-b4 advance. The plan is not as brutal as usual in the 6.Bc4 line, when White usually plays f4-f5 to open the bishop's diagonal. Here the intentions are different.
6... e7e6  7. c1e3 In the past, the move 7.Bb3 was more or less automatic, but recently White has started to experiment with other options. 7... b7b5  8. c4b3  8... f8e7 Black must be very careful with possible sacrifices on e6, so it's recommended to leave the bishop on c8 for now.